The present invention relates to a copying apparatus wherein an image corresponding to an original is formed under the conditions or parameters controlled in accordance with the nature of the original. More particularly, the present invention relates to a copying machine printer or the like.
U.S. Pat. No. 2,956,487 discloses that a reproduced image is improved by controlling the image formation in response to detection of a quantity of light or a surface potential which may be representative of the density of the original. There are some other proposals in this respect after the above U.S. Patent.
In a copying apparatus, an image is formed on the photosensitive drum with the scanning caused by the relative movement between the original and an optical system including an illumination lamp. During such an image forming process, an image forming condition may be automatically changed. More particularly, it is known that an amount of light reflected by the original is sensed by a photosensor, the output of which is processed and then used for controlling a developing bias or an amount of exposure on a real time basis.
Actually, however, when this idea is implemented, background foggy images result at portions corresponding to the neighborhood of edges of the original.
The cause of this as well as a solution thereto is not known.